Identification of regions on the fusion protein of human parainfluenza virus type 2 which are required for haemagglutinin-neuraminidase proteins to promote cell fusion

• Published in: Journal of general virology 1998-02, Vol.79 (2), p.279-289
• Main Authors: Tsurudome, M, Ito, M, Nishio, M, Kawano, M, Okamoto, K, Kusagawa, S, Komada, H, Ito, Y
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Cell Fusion; Cell Line; Cell Membrane - physiology; Cercopithecus aethiops; HeLa Cells; HN Protein - physiology; Humans; Molecular Sequence Data; Mutagenesis, Site-Directed; Parainfluenza Virus 2, Human - physiology; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - chemistry; Rubulavirus - physiology; Sequence Alignment; Sequence Homology, Amino Acid; Transfection; Viral Fusion Proteins - biosynthesis; Viral Fusion Proteins - chemistry; Viral Fusion Proteins - physiology
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/0022-1317-79-2-279

M Tsurudome, M Ito, M Nishio, M Kawano, K Okamoto, S Kusagawa, H Komada and Y Ito Department of Microbiology, Mie University School of Medicine, Tsu, Japan. [e-mail] Using a plasmid expression system in HeLa cells, we have previously shown that the fusion (F) protein of simian virus 41 (SV-41) induces cell fusion when coexpressed with the haemagglutinin-neuraminidase (HN) protein of human parainfluenza virus type 2 (PIV-2), while the PIV-2 F protein does not induce cell fusion with the SV-41 HN protein. In the present study, we found that the PIV-2 F protein induced extensive cell fusion with the HN protein of mumps virus (MuV), whereas the SV-41 F protein did not. Chimaeric analyses of the F proteins of PIV-2 and SV- 41 identified two regions (designated M1 and M2) on the PIV-2 F protein, either of which was necessary for chimaeric F proteins to show fusogenic activity with the MuV HN protein. Subsequently, two additional regions (P1 and P2) were identified on the PIV-2 F protein, both of which were necessary for chimaeric F proteins to prevent induction of cell fusion with the SV-41 HN protein. Consequently, it was proved that a given chimaeric F protein, harbouring regions P1 and P2 together with either of region M1 or M2, induced cell fusion specifically with HN proteins of PIV-2 and MuV, the same as the PIV-2 F protein. Region M2 was located at the membrane proximal end of the PIV- 2 F1 ectodomain, while regions P1, M1 and P2 clustered together in the middle of the ectodomain. These regions on the PIV-2 F protein may be involved in a putative functional interaction with HN proteins, which is considered to be a prerequisite for cell fusion.